The Italian striker burst onto the scene with an injury-time winner on his United debut against Aston Villa in 2009.
The 20-year-old scored a further four goals for Sir Alex Ferguson's side but his first-team chances have been limited, a situation he admits has been frustrating.
New surroundings: Federico Macheda has joined QPR on loan
'When I had my debut it was great but then I did not have the chance to play every game,' Macheda said. 'When I got on the pitch, I tried to do my best and it wasn't easy.
'I was only 17 then and I knew I could not play in every game. It has been difficult, but I don't want to think about the past.
'Now I am here and I want to do very well here. I had a tough time. I didn't get on the pitch many times but it is a good experience.
'You have everything to learn about bad things as well so I take it as an experience and of course I need to step up to become a real player.
'Now I am young and I need to step up to become a big player. That is what I am looking for.'
Several United academy graduates have gone out on loan in recent times, honing their skills and subsequently becoming key first-team players.
Tom Cleverley and Danny Welbeck are two such examples and players Macheda wants to emulate.